In typical fuel cell systems, anode injectors provide hydrogen to the anode side of the fuel cell stack. A common mode of failure for the anode injectors is to fail in an open state. When the anode injectors fail open, undesirable and uncontrolled amounts of hydrogen is delivered to the anode side of the fuel cell stack. Often, the anode injectors do not signal a failure to the control system, consequently making it difficult to predict a pressure rise or the hydrogen flow in the anode side of the fuel cell stack.
A faulted open injector may cause an increase of pressure on the anode side which can damage the fuel cell stack membrane, and affect the life of the fuel cell stack. The increase in pressure may also damage the fuel cell stack unless the pressure rise is detected and operation of the fuel cell system stopped quickly. Stopping the fuel cell system due to a faulted open injector typically results in the fuel cell being completely inoperable, and an operator being stranded when the fuel cell is powering a vehicle.
It would be desirable to develop a method of operating a fuel cell system capable of detecting the pressure rise caused by a faulted open anode injector, reducing pressure in the fuel cell stack when the fault occurs, taking remedial action to allow continued operation of the fuel cell stack, and militate against a walk-home incident.